Worksheets8th Grade Science Q1 Review
Total questions: 30
Worksheet time: 1hrs 6mins
Name
Class
Date
1.
The diagram above is a model of a molecule of methane. What is the formula for methane?
a)
CH8
b)
C8H4
c)
CH4
d)
C8H8
2.
2Mg + O2 → 2MgO
In the equation above, how many atoms are in the oxygen molecule?
In the equation above, how many atoms are in the oxygen molecule?
a)
2
b)
0
c)
1
d)
3
3.
The formula below represents the most common carbohydrate known as Glucose. Glucose is synthesized by Chlorophyll in plants as they use carbon dioxide from the air and sunlight as an energy source during the process of photosynthesis.
C6H12O6
What information can be determined from the chemical formula?
C6H12O6
What information can be determined from the chemical formula?
a)
The structural arrangement of the atoms in a glucose molecule.
b)
The color of a glucose molecule.
c)
The size of a glucose molecule.
d)
The number of atoms of each element in a glucose molecule.
4.
Which of the following formulas contain the same number of oxygen atoms?
1. Mg(NO)2
2. NH4NO2
3. Ca(ClO2)2
4. Co(NO3)2
1. Mg(NO)2
2. NH4NO2
3. Ca(ClO2)2
4. Co(NO3)2
a)
Formulas 1 and 2
b)
Formulas 2 and 4
c)
Formulas 1, 2, and 3
d)
Formulas 1, 2, and 4
5.
How many atoms are in one molecule of baking soda, NaHCO3?
a)
4
b)
5
c)
3
d)
6
6.
A student placed 2 grams of baking soda in a balloon, and 100 mL of vinegar in a Erlyenmeyer flask. After stretching the balloon across the neck of the flask, the student raised it to drop the baking soda into the flask. He immediately observed foaming bubbles in the flask and the balloon began to expand. The student concluded that -
a)
Only a physical change was occuring
b)
The baking soda and vinegar were products of a chemical reaction
c)
The gas was oxygen
d)
The bubbles indicated that a chemical change was occuring
7.
During an investigation, students dropped a tarnished penny into a solution a acetic acid and sodium chloride. Tiny bubbles formed around the penny, and the penny was less tarnished after two minutes of soaking in the acetic acid and sodium chloride solution. The student inferred that a chemical reaction occured. What evidence supports the students' inference?
a)
The penny experienced a color change, and a gas was produced.
b)
The penny experienced a color change, and a precipitate was formed.
c)
The penny experienced a color change and is in a new state of matter.
d)
The penny experienced a color change and produced light.
8.
Students in a science lab conducted an investigation. Students recored the following observations.
Substance 1 produced light when burned.
Substance 2 dissolved in water.
Substance 3 melted at 100⁰ C.
Substance 4 formed a precipitate.
Which substances produced a chemical change?
Substance 1 produced light when burned.
Substance 2 dissolved in water.
Substance 3 melted at 100⁰ C.
Substance 4 formed a precipitate.
Which substances produced a chemical change?
a)
Substances 1 and 2
b)
Substances 1 and 3
c)
Substances 1 and 4
d)
Substances 2 and 3
9.
Which of the following equations follows the law of conservation of mass?
a)
3H2O → 3H2 + 3O2
b)
C2H4 + 3O2 → 2CO2 + 2H2O
c)
C + 4H2 → CH4
d)
2Na + Cl → NaCl
10.
How can a student determine that a chemical reaction demonstrates the law of conservation of mass?
a)
Students can compare the products and reactants to determine if the same molecules are present before and after the reaction.
b)
Students can compare the products and reactants to determine if the same number of atoms of each element are present before and after the reaction.
c)
Students can compare the products and reactants to determine if the same number of molecules are present before and after the reaction.
d)
Students can compare the products and reactants to determine if the same elements are present before and after the reaction.
11.
In a chemical equation, it is true that -
a)
the reactants and products can have different numbers of atoms for each element.
b)
there can be different elements on the reactants side and the product side.
c)
an element or compound must be accompanied by a phase change.
d)
the coefficients indicate the number of molecules of each reactant used and the number of molecules of each product made.
12.
What is the correctly balanced chemical equation for the formation of rust, Fe2O3, forming when oxygen, O2 reacts with iron, Fe?
a)
O2 + Fe → Fe2O3
b)
3O2 + 4Fe → 2Fe2O3
c)
3O2 + 2Fe → 2Fe2O3
d)
2O2 + 4Fe → 2Fe2O3
13.
What conclusion can you make about the elements shown above?
a)
Phosphorus has more valence electrons than nitrogen.
b)
Carbon has fewer protons in its nucleus than nitrogen.
c)
Phosphorus is more like silicon than it is like nitrogen.
d)
Aluminum is smaller than carbon.
14.
Refer to the Venn diagram above. Which of the following traits do Element I and Element II have in common?
a)
The same atomic number
b)
The same atomic mass
c)
The same number of energy levels
d)
The same number of valence electrons
15.
Refer to the Venn diagram above. Which of the elements would have the most similar chemical properties as Element I?
a)
Tantalum
b)
Scandium
c)
Potassium
d)
Strontium
16.
Which of the atom models above represents a stable atom that will not react?
a)
Model A
b)
Model B
c)
Model C
d)
Model D
17.
Based on what you know about the organization of the Periodic Table, which two elements shown above would have the most similar chemical properties?
a)
Sodium and Magnesium
b)
Potassium and Calcium
c)
Potassium and Magnesium
d)
Sodium and Potassium
18.
The most reactive metal is one with -
a)
4 valence electrons
b)
1 valence electron
c)
2 valence electrons
d)
3 valence electrons
19.
When determining an element's chemical properties, the most important subatomic particle to look at is -
a)
protons
b)
valence electrons
c)
neutrons
d)
positrons
20.
In order to perform an experiment, a chemist needs an element that has similar properties of potassium (K) but has a lower atomic mass. Which element should the chemist select for the experiment?
a)
Rubidium (Rb)
b)
Sodium (Na)
c)
Magnesium (Mg)
d)
Calcium (Ca)
21.
Which of the following groups in the Periodic Table is made from reactive metals?
a)
Group 1
b)
Group 6
c)
Group 17
d)
Group 18
22.
Which of the following groups in the Periodic Table is made from non-reactive elements?
a)
Group 1
b)
Group 4
c)
Group 17
d)
Group 18
23.
Using the Periodic Table, which of the following groups of elements has the smallest atomic number in Period 4?
a)
Group 1
b)
Group 4
c)
Group 17
d)
Group 18
24.
Atoms of which of the following elements have the most similar chemical properties as Cadium (Cd) atoms?
a)
Zinc (Zn)
b)
Gold (Au)
c)
Copper (Cu)
d)
Silver (Ag)
25.
Refer to the image above. Which of these is NOT found in the nucleus of an atom?
a)
Neutrons
b)
Protons
c)
Atomic mass
d)
Electrons
26.
Which of the atom models above represents a reactive metal?
a)
Model A
b)
Model B
c)
Model C
d)
Model D
27.
Which of the following is the atomic mass of the atom represented in the above graphic?
a)
17 amu
b)
16 amu
c)
33 amu
d)
32 amu
28.
Which of the following elements is represented by the above graphic?
a)
Sulfur
b)
Chlorine
c)
Argon
d)
Arsenic
29.
Which of the following is the atomic number of the atom represented in the above graphic?
a)
16
b)
17
c)
18
d)
33
30.
Which of the following is the number of valence electrons in the atom represented above?
a)
16
b)
17
c)
6
d)
8
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